What is difference between Interface and abstract claa

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Accepted Answer

Interfaces are pure abstract classes while abstract classes can have concrete methods.

Interfaces cannot have any implementation while abstract classes can have some implementation.
A class can implement multiple interfaces but can only inherit from one abstract class.
Interfaces are used for achieving multiple inheritance in Java.
Abstract classes can have constructors while interfaces cannot.
Interfaces are used for defining contracts while abstract classes are used for defining common characteristics among related classes.